Taking these one at a time:

Is it possible to turn masts to catch winds, like in Sea of Thieves? does it require a lot of men to rotate it? will it need ropes?

Assuming a square-rigged ship, you're not turning a mast (those are the vertical things), you're turning the yardarms from which sails are suspended or the booms or gaffs that stretch them out. And yes, you trim the yardarms to catch wind -- it's a bit of a laborious process that takes a great deal of manpower.

Where is the Kitchen or Galley or whatever it's called, located usually? and what does it have?

In ships in the period I study, the galley would have a large stove for boiling water and possibly spits for roasting meat -- it would be located forward in the ship, under the forecastle deck, and set on firebricks so as not to set the ship on fire. Here's a tour of the galley on HMS Victory.

How did people repair holes on the ship in mid battle? Planks and nails?

If you're repairing in mid-battle, you're having a bad time. But you could stuff shot holes with soft things (rolled hammocks) until you have time to stop leaks properly, with lumber and nails, or you're able to dock and repair the ship properly.

What is the main use of the Bilge Pump?

To pump out the bilges, of course 😉 The bilges of a ship are the lowest part of the ship, near the keel, and all ships leak, so pumping is necessary to get the water out. (The first rule of ships and boats is that water should stay on the outside.)

Where are the toilets usually located?

The ship's captain had a toilet in a quarter-galley on the back corner of the ship, and officers and crewmen could use chamber-pots or just pee over the side, but the official toilets (called a "head") were at the bow of the ship, on either side of the bowsprit. Here are the heads on the Swedish ship Vasa (they're the square boxes, which would have been fitted with seats).

How many crew members should there be on average

It depends a great deal on the size of the ship and its intended use. A full-size warship like HMS Victory could have up to 850+ men on board, but that size of crew was required to fight and sail the ship in battle and provide redundancy. A large merchant ship of the same time period might set off on a run from Greenwich to Bombay with a crew of a dozen or so.

Could a full crew operate a ship properly without any experience or actual knowledge on how to operate a ship? Is a little bit of knowledge enough? Should they be properly trained to do so?

No, sailing is a specialized skill and a crew of landlubbers would not have a good outcome when sailing (the water would tend to come on the inside of the ship). British ships in the period I study would impress non-sailors in times of extreme need (there was always simple manual labor to be done), but they would need some training to become useful sailors.

Where is the steering wheel located? Out in the open or under a ceiling?

It depends on the ship somewhat, but in most cases it would be in front of the mizenmast, on the open deck (so the helmsmen and timoneer can see the set of the sails). Some ships would have a light roof or could stretch an awning over the wheel, but it was not common.

I've written a lot about ships and shipbuilding, if this is an interest of yours: https://www.reddit.com/r/AskHistorians/wiki/profiles/jschooltiger